This invention relates to an adhesive composition.
Such compositions may be used for drug delivery, wound care or to attach appliances or devices to human skin. One example of a protective dressing is described in U.K. Patent No. 1,088,992. Since the publication of that patent, many adhesive compositions for these purposes have been proposed.
G. D. Searle & Co. of Illinois proposed in U.S. Pat. No. 4,296,745 (1981) an adhesive surgical dressing which comprises a backing material provided on one side with a composition comprising per 100 parts, by weight, of a non-biodegradable, tacky, polymeric binding agent, from 12 to 25 parts, by weight, of an inert reinforcing filler and a coating on at least the intended skin contacting face of the dressing of a non-biodegradable, water-activated adhesive/thickener, the composition having an aqueous swell value of from 5 to 40% and a cold flow value of from 50 to 90%. It may be used for ostomy applications. This adhesive is said to obviate certain disadvantages of known materials in that it adheres satisfactorily to moist surfaces, it absorbs moisture and maintains its adhesion and is physiologically acceptable.
Kao Corporation in Japanese Patent Application 1982-058535 disclosed a pressure sensitive adhesive sheet comprising a base fabric which has stretching properties in 1 or 2 directions, that is, a degree of 20% stretching at 1.50 g/cm load, and an adhesive layer. This adhesive layer comprises (a) 3.25 wt. % water soluble polyol of hexylene glycol, polyethylene glycol of less than 1000 mol. wt., glycerine or sorbitol, (b) 1.25 wt. % water soluble or water swelling polymer and (c) remaining wt. % of adhesive agent(s) (where sum of (a) +(b) must be more than 6 wt. %.
E. R. Squibb & Sons, Inc. in European Patent (EP) 307187 disclosed a dressing comprising a flexible backing member and a pressure sensitive adhesive layer. The adhesive layer comprises one or more polyisobutylenes, elastomers, and one or more moisture absorbing, moisture transmitting, water soluble and/or water swellable agents. According to the teaching in EP 307187, a dispersion of an active ingredient in a medium compatible with the adhesive layer is laminated to the skin contacting surface.
The same Applicant in EP 297769 taught that a pressure sensitive acrylic adhesive mass is made hydrophillic by blending one or more water/moisture absorbing, water/moisture transmitting substances into the acrylic mass. The resulting adhesive is particularly suited for medical use such as in bandage and wound dressing type products. The disclosed production method uses solvent and can make pads of thickness typically up to 0.1 mm compared with typically in excess of 0.5 mm for the preferred products according to the present invention. Also, the additives would be leachable.
Nitto Denko Corporation in EP 528191 disclose a dressing comprising a backing and an adhesive layer, wherein said backing is moisture-permeable and said adhesive layer comprises an adhesive composition comprising a rubber-based adhesive, a polymer having a water-absorbing property and/or a water-swelling property and a metal oxide and/or a metal salt, said polymer having the water-absorbing property and/or the water-swelling property being a polymer containing is a functional group having an ability to form a salt and/or to co-ordinate. The present invention does not rely on a metal oxide or a metal salt for acceptable operation.
LTS Lohmann Therapie-Systeme in PCT Application WO95/31188 disclose a system for delivering substances contained in hot-melt type pressure-sensitive adhesives with a uniform or irregular distribution of the substances characterised in that the hot-melt type pressure-sensitive adhesive is hydrophillic and contains at least one water-soluble or at least water-swellable polymer, at least one water-soluble, hot-melt type adhesive resin and the substance to be delivered.
In WO95/31514 of SULC there is disclosed a composite pressure sensitive adhesive particularly suitable for temporary gluing medical and cosmetic means to the body surface from which it can be easily removed by liquid water or by innocuous diluted aqueous solutions. Such a product is described as a gelled mixture of a water swellable, water insoluble polymer, soluble in polar water-miscible solvents boiling at atmospheric pressure at temperatures higher than 100.degree. C. as well as their mixtures with minor amounts of water; a hydrophillic water swellable polymer, insoluble in water as well as in polar water-miscible solvents boiling at atmospheric pressure at temperatures higher than 100.degree. C.; and a polar water-miscible innocuous solvent boiling at atmospheric pressure at temperatures higher than 100.degree. C., if desired mixed with a minor amount of water.
Reference is also made to GB-A-2046764 and U.S. Pat. No. 4,768,503 which describe a polymeric composition adhesive for use in skin contact applications. The composition uses a chemically cross-linked hydrophilic polymer and a support matrix such as a high molecular weight hydrophobic polymer. The hydrophilic polymer is water-swellable, but water insoluble. The composition preferably includes a tackifier which may be provided by a low molecular weight fraction of a hydrophobic matrix, or by a distinct adhesive component such as gum or a low molecular weight polymer. The composition is said to be especially suitable for post-surgical drainage applications.